package 
  {
  
          public class @ax-actionscript-book-GeometricShapes-com-example-programmingas3-geometricshapes-EquilateralTriangle extends actionscript_book_GeometricShapes_com_example_programmingas3_geometricshapes_RegularPolygon
          {
              // Inherits the numSides and sideLength properties from RegularPolygon
          
                  public function @ax-actionscript-book-GeometricShapes-com-example-programmingas3-geometricshapes-EquilateralTriangle(len:Number = 100):void
                  {
                          super(len, 3);
                  }
                  
                  public override function getArea():Number
                  {
                      // the formula is ((sideLength squared) * (square root of 3)) / 4
                      return ( (this.sideLength * this.sideLength) * Math.sqrt(3) ) / 4;
                  }
                  
                  // Inherits the getPerimeter() method from RegularPolygon
                  
                  // Inherits the getSumOfAngles() method from RegularPolygon
                  
                  public override function describe():String
                  {
                      // starts with the name of the shape, then delegates the rest
                      // of the description work to the RegularPolygon superclass
                      var desc:String = "This shape is an equilateral Triangle.\n";
                      desc += super.describe();
                      
                      return desc;
                  }
          }
  }